Septic tank risers and lids in Michigan: advisory, rule and safety

What EGLE’s advisory says

In December 2008 EGLE’s Technical Advisory Council published an advisory on septic tank risers and lids. It recommends installing risers on any tank opening that may need access. It gives typical riser diameters of 24 to 30 inches, says the riser should attach to the tank watertight, and describes what a lid should be: waterproof, resistant to ultraviolet light and corrosion, fitted with a gasket, and rated for a wheel load of at least 2,250 pounds when it sits at ground level. The advisory says risers brought up to grade make inspection and pumping simpler, and that they also act as a visual reminder to the owner that the tank is there.

An advisory is guidance, not a rule, and a county can ignore it. Even so, it is a specific Michigan government statement of what a good riser and lid look like, which makes it a fair checklist when you compare quotes.

What is a rule, and what only applies to loan work

The nearest thing to a rule for ordinary installations is in the state Criteria for Subsurface Sewage Disposal, a guideline document and not a statute. They require at least one 18-inch opening per tank compartment, extended to the surface, with a secure cover designed to keep surface water from getting in. So the state requires access at the surface and the advisory describes how to do it well.

EGLE’s septic replacement loan program sets a stricter condition for the work it funds. Septic tanks, secondary treatment tanks and pump chambers must have a watertight riser to grade and a secured secondary safety component, and existing tanks that are reused must be upgraded to meet it. That binds loan-funded work only, but it shows what EGLE considers the standard when public money is involved. The pump record form EGLE uses for the program has separate yes-or-no lines for risers to grade and for a secondary safety device, so a pumper working on a loan job has to look for both.

What a riser changes at a pumping visit

Oregon State University Extension recommends installing risers from the central manhole and the inspection ports to the surface and marking the tank location, so that the openings can be found easily. It also explains why the central manhole matters. The tank should be emptied through the large central manhole and not through the baffle inspection ports, because pumping through the ports can damage the baffles. A riser on the central manhole makes that the easy way to do the job, and it makes the baffle check that Oregon State asks for before the tank is closed easier to carry out at every pumping.

EGLE’s yearly owner checklist begins with opening and inspecting all tanks, and the pump record asks whether the tank location was accessible, so a buried lid shows up as a cost in time at every visit. The advisory covers any opening that may need access, and EGLE’s loan standard lists pump chambers alongside septic tanks, so a pumped system may need more than one riser.

Safety: lids, children and the inside of a tank

EGLE says that after a flood owners should not leave a tank opening uncovered and should secure, repair or replace covers so that debris and people cannot fall in. The same logic applies at any time of year. A cracked or missing lid is an urgent repair and not a cosmetic one.

Oregon State is blunt about the inside of a tank. It says a septic tank produces gases that can kill within minutes and that any baffle or tank repair should be done from the outside. EGLE separately tells owners not to service a septic system themselves because of disease, dangerous gases and electric shock.

Who may install one, and what is still unanswered

Neither a statewide license for septic installers nor a state rule on permits for adding a riser to an existing tank appears in the sources we can cite. Counties regulate work on septic systems, and some license installers. Oakland County, for one, makes it unlawful to install, alter or repair a system without a county license. Call your county health department before you hire, and ask whether the work needs a permit.

Two common questions have no government answer in the sources we can cite. EGLE’s advisory does not address whether a riser keeps a tank from freezing, and none of the other sources does either, so we make no claim either way. Nor did any of them give a Michigan price for a riser. A local installer who can see your tank depth and cover is the better person to ask about both.

Questions to ask an installer

Use the advisory as a script. Ask whether the riser attaches to the tank watertight, whether the lid has a gasket and resists sunlight and corrosion, what wheel load it is rated for if it sits at ground level, how the lid is secured against a child or a pet, and whether the installation includes a secondary safety component of the kind the loan program requires. Ask for the riser, lid, gasket and labor as separate lines on the quote, since no government source gives a price to compare against. Have the installer note the opening locations on a sketch you can keep with the pump records.

Buying a house with a buried tank

Ask the seller and the county for the as-built drawing and the last pump record. EPA says the local permitting authority usually holds the permit and as-built drawing, and the drawing shows where the lids lie. If the tank has no riser, plan one into your first pumping, since EGLE’s advisory and Oregon State both recommend it. If it has risers, check each lid for a gasket, a fit and a rating, and check that the opening is secure. The pumping receipt guide lists what the pumper should record, and the riser and lid page has the service details.